A novel circular polarized dielectric antenna array (DRA) for millimeter-wave applications at 30 GHz is presented in this paper. The unit element array is a flower-shaped DRA fed with a cross slot. To obtain circular polarization, a sequential network combined with the cross slots is used to feed the 2×2 array. The prototype of the proposed antenna array is fabricated and measured to obtain a wide resonance bandwidth from 27 GHz to 38 GHz frequency band. Furthermore, this left-hand polarized antenna array has achieved a peak gain of 9.5 dBi with 3-dB axial ratio at 30 GHz. The proposed DRA array with wideband resonance and gain bandwidth has the potential to be used for millimeter-wave wireless communications at the 30 GHz band.

In this work, a simple propagation channel model for microwave-based pinless subsea connectors in the 5 GHz band is presented. Both high electromagnetic attenuation in seawater due to absorption and the near-field working conditions typically present for underwater connectors are taken into consideration. Therefore, a simplified path loss model based on linear regression is identified. The study shows that high-speed pinless subsea connectors are a reality over several cm of seawater gap when appropriate microwave receiver technology is selected with sensitivities of about −100 dBm. Experimental results show that both half-duplex gigabits-per-second and full-duplex 100-Mbps technologies have a strong potential to be developed in the 5 GHz band.

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